Adopted this girl. She’s so skinny. Help please

Hey All, looking for advice for my Maine coon kitten. We rescued this girl from a neglectful home. When we got her she was filthy and way too thin. At 8 months old she was only 8 lbs and I can feel every bone in her body. I had a vet come to the house and she said she seems otherwise healthy. But it’s been a month now and even offering her lots of kitten food and plenty of wet food, she is barely gaining a few ounces. Any advice on how to help her gain weight?